I've asked this before, but here's a new inquiry, since the old one produced no real meaningful answer.
If your rifle likes 20/1 and you know it, do you think there might be any notable difference if you hit on two batches of mix that were actually 19/1 and a succeeding one at 21/1? I ask because I have not experimented with alloy as much as some of the rest of you who have become expert in this area. It seems to me that it's like having to measure a precise amount of sugar into your coffee cup, though most taste buds wouldn't know the diff. Am I wrong?

Ray it all boils down to what each individual rifle likes and the design of the bullet being used. In other words only you can determine which alloy will add a point to your score and which of those that would actually drop a point instead. When we think about score shooting one needs to understand that we are actually group shooting. So the real goal is to achieve the smallest groups as is possible and then to be able to place them into the 25 ring. Which powder, primer, bullet, seating depth and alloy to use is only something that you can determine for yourself. How by getting out and shooting groups and letting them tell you what is actually the best choice for you to use. For myself 16-1 has proven to be the right choice by consistently providing the smallest 200 yard groups for both the 28-35 and 25-35. For the 38-55 it was 30-1 and for the 32-40 it was dependant on which bullet was used and it was 20-1 and 16-1 and when I say which bullet was used I did not use the same bullet design for 100 yards as I did for 200 yard competitive use.

Beltfed I am not trying to be argumentive but the choice of alloy also directly relates to their shrinkage rates. When one says a .001 over groove diameter one also must understand it is now down to a .0005 per-side. Being one who now makes his own bullet moulds I can honestly say a simple change in ones alloy choice would by far beyond exceed that .0005 tenth per side fit that he thinks he gets. Also in all honesty very few have the ability or I should say it's very difficult for one to be able cast bullets that would retain that .0005 per side fit to a single batch of bullets to be used in a match. While also keeping in mind that they would all also have to perfectly round and to weigh the same within three and not to exceed four tenths.